Differential Cross Sections for (n, n′γ) Reactions in Several Nuclei

Differential cross sections for the production of gamma rays by inelastic neutron scattering have been measured and compared with the predictions of the statistical model, employing a diffuse surface complex potential to represent the neutron-nucleus interaction. Transitions have been observed in ${\mathrm{Mg}}^{24}$, ${\mathrm{Mn}}^{55}$, ${\mathrm{Fe}}^{56}$, and ${\mathrm{Pb}}^{206}$. Predictions of the statistical model were in good agreement with total ($n, n^{\prime }\gamma$) cross sections measured for first-excited state transitions in ${\mathrm{Fe}}^{56}$ and ${\mathrm{Mg}}^{24}$, and in agreement with measured transition rates from the second and third excited states of ${\mathrm{Fe}}^{56}$. Angular distributions for ${\mathrm{Mn}}^{55}$ transitions are consistent with recent spin assignments for the second and third excited states, but the comparisons of the measured and calculated total cross sections are not as satisfactory as the comparisons in ${\mathrm{Fe}}^{56}$ and ${\mathrm{Mg}}^{24}$.